The dynamics of surface detachment and quorum sensing in spatially controlled biofilm colonies of Pseudomonas aeruginosa
type: CreativeWork
description: Biofilms represent a highly successful life strategy of bacteria in a very broad range of environments and often have negative implications for industrial and clinical applications, as their removal from surfaces and the prevention of biofouling in the first place represent formidable and to date unmet challenges. At the same time, biofilms modulate important natural processes, including nutrient cycling in rivers and streams and the clogging of porous materials. Biofilm development is a dynamic process, dependent on a host of cellular and environmental parameters that include, among others, hydrodynamic environment and the communication among cells (QS). Here we used microfluidics and micro-contact printing, paired with video-microscopy and image analysis, to study several aspects relating to the temporal dynamics of bacterial biofilms. Beyond reporting on specific findings from these experiments, we demonstrate how these innovative technologies can aid in obtaining a new layer understanding on biofilm processes and biofilm removal, thanks to unprecedented control over the biofilm's microenvironment. In a first set of experiments (chapter 2), we cultured Pseudomonas aeruginosa biofilms in a microfluidic channel for different times, after which we used the passage of an air plug as a mechanical insult to drive detachment. We found that the adhesion properties of an early-stage biofilm have a strong correlation with the time of growth and that biofilm detachment can occur in a spatially heterogeneous manner characterized by a regular pattern of 'holes' in the original biofilm. The resulting spatial distribution of bacteria correlates with the distribution of the extra polymeric substance (EPS) matrix before the insult, indicating that the locations of the holes correspond to where there was the least EPS. These results demonstrate that the detachment mechanism is a competition between the shear force exerted by the external flow and the local adhesion force of a give…
abstract: Biofilms represent a highly successful life strategy of bacteria in a very broad range of environments and often have negative implications for industrial and clinical applications, as their removal from surfaces and the prevention of biofouling in the first place represent formidable and to date unmet challenges. At the same time, biofilms modulate important natural processes, including nutrient cycling in rivers and streams and the clogging of porous materials. Biofilm development is a dynamic process, dependent on a host of cellular and environmental parameters that include, among others, hydrodynamic environment and the communication among cells (QS). Here we used microfluidics and micro-contact printing, paired with video-microscopy and image analysis, to study several aspects relating to the temporal dynamics of bacterial biofilms. Beyond reporting on specific findings from these experiments, we demonstrate how these innovative technologies can aid in obtaining a new layer understanding on biofilm processes and biofilm removal, thanks to unprecedented control over the biofilm's microenvironment. In a first set of experiments (chapter 2), we cultured Pseudomonas aeruginosa biofilms in a microfluidic channel for different times, after which we used the passage of an air plug as a mechanical insult to drive detachment. We found that the adhesion properties of an early-stage biofilm have a strong correlation with the time of growth and that biofilm detachment can occur in a spatially heterogeneous manner characterized by a regular pattern of 'holes' in the original biofilm. The resulting spatial distribution of bacteria correlates with the distribution of the extra polymeric substance (EPS) matrix before the insult, indicating that the locations of the holes correspond to where there was the least EPS. These results demonstrate that the detachment mechanism is a competition between the shear force exerted by the external flow and the local adhesion force of a give…
author: Jang, Hongchul
language: eng
keywords: Civil and Environmental Engineering.
license: http://dspace.mit.edu/handle/1721.1/7582
date published: 2014
date modified: 2026-07-22T22:22:02Z
provider: MIT
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: Massachusetts Institute of Technology

PropertyValue
property ID: Handle
value: http://hdl.handle.net/1721.1/88390